Fights less about losing energy settled within a day (7)
I believe the answer is:
tussles
'fights' is the definition.
(tussling is a kind of fighting)
'less about losing energy settled within a day' is the wordplay.
I cannot really see how this works, but
an anagram of 'less' is 'ssle' which is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for tussles that I've seen before include "Struggles" , "Scuffles, dogfights" , "Scraps" .)